Theoretically yes but by then you wont get 32bit OS's anyway. You could in theory keep a machine running with a 32bit OS until you need that sort of on board Ram on a GPU but i recon it would need to be left in a couple of wills first :lol:
Also just for the sake of it the machine wouldnt have any actual Ram if the GPU took up all the address space so wouldnt work anyway. Im not 100% sure but i think that the GPU gets given space first and the system Ram is addressed last.
so if you are running a 2gb card now you are limiting your OS to 1.2 ish of Ram.
Mactronix